1. Field of the Invention
This invention relates generally to sliding doors, and more specifically to top guides for guiding sliding doors along top tracks.
2. Description of Related Art
Sliding panel doors, such as those used in closets, are constructed from thin panels that gain rigidity from the application of a perimeter frame formed by two side, one top, and one bottom roll formed or extruded metal sections that are mechanically joined at each corner by means of a metal or plastic joining plate. The weight of the panel door is typically supported by a bottom track, and the door is provided with wheels or other slidable elements that can slide or roll within the bottom track. The top portion of the door is often retained and guided in a top “E” section track, which provides downwardly depending leg portions defining vertical surfaces in which the upper portion of the panel door is retained and guided. Particularly, the upper portion of the panel door is typically provided by a top guide assembly that is attached to the metal or plastic frame joining plate at each top corner of the door. The top guide assembly typically includes a pair of top guide wheels (or rollers or other slidable elements) each rotatable about a vertical axis. As the door travels along the bottom and top tracks, the top guide wheels rotate against the inside parallel vertical edges of the E track and keep the sliding door positioned centrally within the track cavity. U.S. Pat. No. 6,449,906 illustrates one such conventional top guide and is incorporated herein by reference in its entirety.
When the top and bottom tracks are perfectly parallel and the top guide assemblies are properly mounted to the sliding door, the top guide wheel axes are perfectly perpendicular to the direction of travel of the sliding door, and the top guide wheels roll smoothly along the inside parallel vertical edges of the top E track. However, in some installations, the top and bottom tracks are not perfectly parallel to each other (i.e., the top and bottom tracks angle toward each other) due to variations and imperfections in the floor, ceiling, or other substrate onto which the tracks are mounted. These imperfections may occur over time with the settling of the building or structure. When the top and bottom tracks are so skewed, the top guide wheel axes will not be perpendicular to the direction of travel of the sliding door, which follows the bottom track. Such a misalignment of the top guide wheel axis relative to the direction of travel of the sliding door may also result from a misaligned attachment of the top guide assembly to the sliding door. Consequently, the natural rolling path of the top guide wheels will be skewed relative to the actual direction of travel of the sliding door. The skewed path over which the top guide wheels roll causes the top guide wheels to vibrate or jitter as they attempt to follow their natural path, but are forced to follow the actual path of the sliding door. This vibration often generates noise.